Issue 53

A. Chatzigeorgiou et alii, Frattura ed Integrità Strutturale, 53 (2020) 306-324; DOI: 10.3221/IGF-ESIS.53.24

 Moves the CTE according to the declared crack increment da.  Re-mesh the structure (surfaces).  Creation of the crack at the re-meshed area.

 When the structure is load free, the crack is completely closed (Fig. 11,a). Because of the re-meshing, the elements that are located at both sides of the crack line have common nodes (blue nodes in Fig. 11,a). These nodes are coincident, and FEMAP joins them. Therefore, we have a crack line, but not a crack. In order to create at every step the new crack (the old one, plus a new with an increment da), the code duplicates the nodes located at the crack line. After the duplication, one node goes to the element above the crack line and the other one, in the element below the crack line. The result is shown in Fig. 11,b.  Analysis of the load case.  Calculation of the SIFs of the new crack.  Extraction of the new data in order to fill the Tab. 2 with the results, and the diagrams in Fig.10.

Crack Size (mm)

Run No.

K I

K II

K III

Keq

dN

N (total)

1

108

1454.9

-22.1

0

1455.4

2490

2490

Table 2: Part of the table created by the proposed code with the results after the first step.

 End of step. If the SIFs are higher than the Δ Kth, or the step number is lower from the maximum number of iterations, then the above procedure will be repeated from the beginning. In Fig.12, it is presented the flowchart which describes the above-mentioned functionality.

Figure 8: FEMAP's typical Desktop.

Figure 9: Focus on the Crack button.

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